Develop Reference

How do I add child <li> elements to <ul> without removing current children

How do I iteratively add children elements to a (for example) a .
<ul id="my-list">
<li>item 1</li>
<li>item 2</li>
</ul>
If I have a JS script that runs something like this several times:
document.getElementById('my-list').appendChild('someListItemICreated')
the current 2 list items are removed. How do I add new li items to the ul without losing the current list itmes?

You need to provide an element as the argument for appendChild and not a string. Like this:
const li = document.createElement("li");
li.innerText = "Item 3";
document.getElementById("my-list").appendChild(li);
<ul id="my-list">
<li>Item 1</li>
<li>Item 2</li>
</ul>
A much easier and a cleaner approach that I prefer in most of cases is:
document.getElementById("my-list").innerHTML += "<li>Item 3</li>";
<ul id="my-list">
<li>Item 1</li>
<li>Item 2</li>
</ul>

const c = document.createElement('li');
c.innerText = 'item 3';
document.getElementById('my-list').appendChild(c);
<ul id="my-list">
<li>item 1</li>
<li>item 2</li>
</ul>

I think you need to be more specific with what your code is actually doing, but I can say that someListItemICreated should not be a string, if that's what you're passing. Here's an example I made that's similar to what you're referring to that runs fine.
<ul id="my-list">
<li>Item 1</li>
<li>Item 2</li>
</ul>
let someListItemICreated = document.createElement("li");
someListItemICreated.appendChild(document.createTextNode("item 3"));
document.getElementById("my-list").appendChild(someListItemICreated)

is it possible, to add auto incremental classes to a list by using jquery or javascript

is it possible, to add auto incremental classes to a list
<ul id="list">
<li>Element 1</li>
<li>Element 2</li>
<li>Element 3</li>
<li>Element 4</li>
<li>Element 5</li>
</ul>
Now, If I hover on Element 3 then, add auto incremental classes to li like example below...
<ul id="list">
<li class="left2">Element 1</li>
<li class="left1">Element 2</li>
<li>Element 3</li>
<li class="right1">Element 4</li>
<li class="right2">Element 5</li>
</ul>
Again if hover on Element 1 then, add auto incremental classes to li like example below...
<ul id="list">
<li>Element 1</li>
<li class="right1">Element 2</li>
<li class="right2">Element 3</li>
<li class="right3">Element 4</li>
<li class="right4">Element 5</li>
</ul>
sorry about my poor English. Thank you.

$('li').hover(function() {
$('li').removeClass();
var next = $(this).nextAll();
next.each(function(i, v) {
$(this).addClass('right' + (i+1))
})
var prev = $(this).prevAll();
prev.each(function(i, v) {
$(this).addClass('left' + (i+1))
})
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul id="list">
<li>Element 1</li>
<li>Element 2</li>
<li>Element 3</li>
<li>Element 4</li>
<li>Element 5</li>
</ul>
Use .prevAll() and .nextAll()
Description: Get all preceding siblings of each element in the set of matched elements, optionally filtered by a selector.
Description: Get all following siblings of each element in the set of matched elements, optionally filtered by a selector.
then iterate on the li and assign the index. make sure to remove the li classes so it wont stack up

Based on example, I cleared all the class in <li> when mouseenter anyone of the <li> and add new class for them.
left1+n will add to previous all <li> and right1+n will add to next all <li>
$("#list > li").on("mouseenter", function(){
$("#list > li").attr("class", "");
$(this).prevAll("li").each(function(i) {
$(this).addClass('left' + (i+1));
});
$(this).nextAll("li").each(function(i) {
$(this).addClass('right' + (i+1));
});
});

HTML List Tags - how to give each <li> diffrent color from other?

how to give each <li> different color from other on Html
<ul>
<li>Item 1</li>
<li>Item 2</li>
<li>Item 3</li>
<ul>
so, Iam looking to Display Items as the Following:
Item 1 In red color
item 2 In blue color
item 3 In green color
What is the best way to do it ?

Create different classes like this in css
.redText
{
color:red;
}
.blueText
{
color:blue;
}
.greenText
{
color:green;
}
And then in your html
<ul>
<li class = "redText">Item 1</li>
<li class = "blueText" >Item 2</li>
<li class = "greenText">Item 3</li>
<ul>
<ul>
JSFIDDLE DEMO

Try style component for each list.
<ul>
<li style="color:red">Item 1</li>
<li style="color:blue">Item 2</li>
<li style="color:green">Item 3</li>
</ul>

jQuery and selecting the next list items objects

I have a nav built with a list and sub nav as lists inside a parent list. The sub nav resides in the next list item to it's corresponding main nav link:
This sits in a div with an id of 'nav'
<ul>
<li>Nav main 1</li>
<li>
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
<li>Nav main 2</li>
<li>
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
</ul>
Currently I have the following jquery:
$(document).ready(function() {
$("#nav ul li a[href^='#']").each(function(){
if ($(this).next().is(':visible')) {
$(this).next().hide();
} else {
$("#nav ul li a[href^='#']").each(function(){
$(this).next().hide();
});
$(this).next().show();
}
});
I thought this would work to make all the sub menu's hide and then show the one that had been clicked on. For some reason nothing happens. I have checked the console (firebug) and there is no error shown.
Getting frustrated with it now! :-/
EDIT: Here is the answer:
$(document).ready(function() {
$("#nav ul li a[href^='#']").each(function(){
$(this).parent().next().hide();
$(this).click(function() {
if ($(this).parent().next().is(':visible')) {
$(this).parent().next().hide();
} else {
$("#nav ul li a[href^='#']").each(function(){
$(this).parent().next().hide();
});
//then reshow and label the clicked nav
$(this).parent().next().show();
}
});
});
});

HTML:
<div id="nav">
<ul>
<li>
Nav main 1
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
<li>
Nav main 2
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
</ul>
</div>
JavaScript:
var s = $('#nav ul ul').hide();
$('#nav a').click(function() {
var u = $(this).next();
u.is(':visible') ? u.hide() : ( s.hide(), u.show() );
return false;
});
Live demo: http://jsfiddle.net/Tq6LM/1/

Never mind... I have figured it out. Writing it out again must have helped. I needed to call the .parent()
Seems that i was trying to call the next a href, i needed to call the next list!

DEMO: http://so.devilmaycode.it/jquery-and-selecting-the-next-list-items-objects
your Javascript Code should be:
$(function() {
$('#main-nav li').click(function(e) {
e.preventDefault();
$('#main-nav li ul').slideUp(500);
$(this).find('ul:not(:visible)').slideDown(500);
});
});
little bit of CSS
#main-nav li ul { display:none }
your HTML should look like this:
<ul id="main-nav">
<li>Nav main 1
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
<li>Nav main 2
<ul>
<li>sub 1</li>
<li>sub 2</li>
<li>sub 3</li>
<li>sub 4</li>
</ul>
</li>
</ul>

sub nav not directing to page (jquery)

I have basic markup for a drop down nav, nested lists.
The user will click on the top nav item, which will open up the sub nav, but my sub nav links aren't working.
It is in a CMS so I must have the links for the placeholder pages there.
Markup:
<ul class="navtop">
<li>Who
<ul>
<li>Sub Item 1</li>
<li>Sub Item 2</li>
<li>Long Sub Item 3</li>
<li>Sub Item 4</li>
</ul>
</li>
<li>What
<ul>
<li>Sub Item 1</li>
<li>Sub Item 2</li>
<li>Long Sub Item 3</li>
<li>Sub Item 4</li>
</ul>
</li>
</ul>
Javascript:
$(".navtop li").click(function(){
$(this).toggleClass("show");
$(this).siblings(".show").toggleClass("show");
return false;
});
css:
#headernav .navtop li.show ul
{
display: block;
}
I tried adding a 'return true' for $(".navtop li ul li a") but it didn't work.
Suggestions?

Why are you return false to the LI click? I believe that's the problem.
If you take that out, everything should work fine.
If that doesn't work, bear in mind you're attaching the click event to every LI instead of just the top level LIs. Try this instead:
$(".navtop > li").click(function(){
$(this).toggleClass("show");
$(this).siblings(".show").toggleClass("show");
});

Turns out this worked:
$(".navtop > li > a").click(function(){
$(this).parent('li').toggleClass("show");
$(this).parent('li').siblings(".show").toggleClass("show");
return false;
});